"Is the baby trying to latch on?

"Is the baby trying to latch on? He's been fussy for two days, even refusing from the breast ? He throws his head back and won't take the breast. He hasn't pooped in two days. I thought he had stomach pain, but it doesn't seem like it. Yesterday he didn't sleep all day, crying. He fell asleep at 5 pm and slept until 6 am. The sleep was restless, he kept asking for the breast all night."